Process of making concentrated liquid dyestuffs.



UNITED bTrhl hib ALBRECHT SCHMIDT AND OTTO SCHVVAB, OF HiCHST-0N-THE"MAIN, GERlv'lANY; Aklf TO FABBWERKE VORM. MEISTER LUCIUS d; BRUNING, F.HOCHS'JFOIUliEilE-dlAi.

MANY, A. CORPORATKON OF GERMANY.

PATENT PROCESS 3F LllhtKIlilG' QQHCENTEATED LIQUID DYES-T'UFFfi No. sumac. I

Application filed June 21,

" Applicants started with the idea of sii plying the market with sulfurized dyestu s in form of leuoc-coinpounds of a liquid and yet concentrated state, similarly to the concentrated liquid indigo whitereparationsfor indigo vats etc. and with t is object in view, up licants succeeded in finding a proccss by w'iich products are obtained satisfactory both in respect to the mode ofmanuiacture and dyeing.' Said products contain the dyestuffs in a reduced liquid, yet concentrated stable form.

Applicants were guided by the following considerations. and ex erimentsz 'lhe manufacture of sulfurized yestufis, for instance, that of sulfur'blacks, has hitherto been carried out by {precipitating them from the aqueous sulfur-alkaline solution by acids or by the introduction of air until precipitation occurs, the suli 'urized dyestufi' linked to an alkali in the aqueous solution of the fusion in form of the leuco-conround and dissolved in sodium sullid, then idtering and finally dryingthe presscako thus obtained in the air or in a vacuum. This drying is an expensive, tedious and under certain cir cumstancee a dillicult operation herein after set forth.

Applicants have further observed that in dyeing the moist press-cakes, especially in the manufacture of black, other changes occur in the dyestull's than those hitherto known, so that the dycstui'l's, whether dried by air or in a vacuum, become more difficultly sol ublc in sodium sulglid, that is to say, they require for dyeing comparatively more sodium sulfid than--with the same tinctorial power moist dyestufl' quire. This is probab y due to an alteration oi the merka tan groups, an alteration which noticed a so with products dried in the vacuum. It therefore would be econom ically very important, if the dyestufi's could be maintained in the condition ofthis ready solubility and in this reduced state, so that Specifieatidn of letters Patent.

Fresscakes would re- Patented. Got. 20, 190a 1905. flericltl'o.$5fifi,225.

c uired when dyeing. Yet, in order to rener these products marketable, they ought to be of a concentrated and stable form. The moist dyestufif pressmalres are not suited for this purpose, as they become irregular by partially or completely drying up, lose their ready solubility and are no ion or fit for the dyer as they get too solid on thick. The addition of water to render them pasty is of no advantage, as in order to obtain suitable pastes, too much water would have to be added (about two parts), which would render the dyestud too thin for permitting its transmission.

Starting from our observation that dyestuffs of the above condition, that is to say, in an undried state, require much less sodium sulfid when dyeing than do dried dyestu'lls and that such dyestuil's would consequently be more readily soluble in sodium sulhd, applicants have found that the following proc: 'ess leads to liquid, yet very concentrated and stable products, by a process which difl'er's from that of dissolving in sodium 'sulr'id and evaporating to dryness described in German patent No. 127,835. These liquid products press-cakes with sodium sulfid in certain pro portions. These proportions may be deducod from the following; new observations: When the above-mentioned sulturized dyestuil' press-calres are stirred, for instance, with increasing quantities of fused crystallhe mass gradually arrives at a point at which the paste has just become liquid, that is to say, it passes from a doughy condition into a fluid form, no more inso uble pasty pieces are present and the whole will .pass through a viscosimeter. The propor tion jof sodium sulfid necessary to bring about this liquidity is the lower limit for the niahufad ture of a concentrated liquid sulfurized dyecomparatively good numbers, for instance, 200 as compared with 82 for Water, but not as low as when a further limited proportion of sodium sulfid is added; moreover, on standing, the solutions stilibec'dme gelatinous and much thicker. Neverthelcsapreparations with this proportion of sodium sulfid are already suitable for transmission over short distances. When now a further proonly small portions of sodium sulfid are re are obtained by stirring the moist dyestu'tl" stuff. The viscosimeter indicates already lized sodium suliid, the following is observed:

portion of sodium sulfid is added, the solution becomes at first still more liquid, the viscosimcter number falls considerably, but on 1 continued addition of the sulfid the viscosd estuii is formed, the addition of more sodium sulfid eitller produces a sparingly soluble basic salt, or hasthe eiiect of salting out.

I The best degree of viscosit ,is thus between two limits, namely, a lower imit at which just a solution of the dyestuil occurs, and an uper limit, at which no solidification occurs on ong standing. These limits within which this phenomenon ha pens, that is to say, the limits for the best egree of liquiditv, var according to the particular dyestuil use and also, of course, according to the desired concentration. For these reasons no s e cific limits for thapro/portion of sodium su 'd as compared with the weight of the dyestuff are given the limits of'proportion to be observed are distinctly determined .in each case from the foregoing observations, namely, that the undried dyestuii obtained b precipitation is to be treated only with suc proportions of sodium sulfid as to transform this dyestuii into a complete solution which keeps liquid on. standing. This is best ascertained by the use of the viscosimeter, so that preferably liquid-solutions may lie-obtained.

When, for instance, it were essential to state limits, they might be stated as follows 2- from 30 to about 1 50 parts of sodium sulfid (calculated as crystallized salt) to 100 parts of concentrated dyes'tuii (calculated as dry). In the form of these solutions the dyestuffs maintain their shades unaltered when the proportions of sodium sulfid are within the aforesaid limits, even after long standing. All the sodiumsulfid which is added enters into the reaction and combines with the dyestuii so I hat the latter becomes soluble in the form of the new compound, remains dissolved, and that the product contains no excess of uncombi'ned sulfid. l'

In carryin out the process it is of advantage to use t 1e press-cakes in a condition as free from salt as possible, since then the danger of salting out is diminished and dyestuii solutions of very high percentage strength with proportionally low specific gravity, are obtained.

The liquid and yet concentrated products. made according to this lgruucss have reat advantages as compared with dried iso ated dyestuffs. In the first 'place their a plication in the dye-house is much easier, or it'is easier to measure than to weigh. A ain, the use of liquid products will abolish 51c troublesome and unhealthy dust of thedried d estuiis, which has hitherto been unavoida la in handling the latter in the dye-house.

dust. the manufacture of concentrated liquid prodwith these highly concentrated roducts is consequently cheaper, less troub esome and more reliable than dyeing. with dried isolated products. Moreover, the cost of manufacturing these liquid highly concentrated products is less than that of the dried products.

The various advanta es in the roduction are, for instance, the fol owing: T e some and ex ensivedrying on tray orthe like is avoide an operation all the more disagreeable as the drying in the air greatly reduces the tinctorial power and dryin 'ina vacuum is still more expensive, besi es involvin more time; form pieces and require pulverization torender them fit for dyeing, which takes up time, is expensive and unhealthy on account of the All these operations are avoided in ucts. The press cakes obtained are sim ly stirred with the proportion of sodium su d requisite for the manufacture of highly concentrated liquid solutions. These solutions obtained b means of the exact proportion of sodium suv fid need not be condensed and dried as in the case of German patent No. 127,835, which process has also the disadvantage of producing dust bywhich the respirative organs are greatly irritated as a consequenceof the contents of dry sodium suliid besides the further disadvantage of the dye stuff powder thus obtained is the ready loss of its contents of sodium suliid when exposed to the air, Wllloll is not the case with the concentrated solutions obtained by this-process. On the contrary, on their being exposed to the air they are covered by a thin layer, just as with the indigo vat by which the contact with the air is cut oil and the insoluble indigo separates and no longer dyes. Alkali hydrates have no special effect upon the product; alkaline salts, added in a solid state, thicken the product;- steam does not change anything in the constitution of the product except t at the same is thereby unnecessarily diluted.

. Example I. 1347 parts of a press-cake irouble- Products dried on trays the corresponding VlSGOSit-lGS for 1000 grams out No. 259,509 until precipitation is comcryst. sodium 388 .addit'. ofcr at. so- 72, 144 288 432 576 been added, the mass is still thick and contains undissolvcd particles when 800 parts of sodium sulfid have been added, solution has occurred and the viscosimctcr number is for instance 150 as compared with 82 for water; this proportion therefore represents the one limit. of the most favorable condition. When the additiono'f the sodiuin smlid is continued, it is found that when a total of 950 parts of sodium sul'lid has been added the viscosity is 120 and on further addition of, for instance, .3, 5, it) or] 5% of sodium sulfid, calculated on the wcight of the dycstuilsolution, the viscosity increases, until finally, on standing, the dycstull' solution to which the maximum proportion of sodium sullid has been added so idi'lics. 'lhis maximum proportion is the upper limit, as may be seen from the following table:

cryst. sodium 950 addit.olcr vst.so- 2.5 5 15 10 2W},

Example 1].. 6850 parts of a press-cakc containing about 46% of dry matter, obtained by blowing air through the aqueous solution of the product from 1:2:4-dinitrophenol, made according to the French patplcte, and filtering and pressing, are stirred with successive portions of fused crystallized sodium sultid. When about "2500 parts have been added, dissolution occursand the viscosity is 155, water being 82; this number increases gradually on' addition of 2, 5, or 10% of sodium sultid to the solution, until finally,- at about 15% solidification ensues on stand ing. The proportions of sodium sulfid and of concentrated dyestufi', calculated at-a concentrat1on oi the dyestuti solution of 34% in respect of the dry dyestuit as free as possible from salt, were, for instance, as follows: oryst. sodium 750 nddit. of crystall. 70 140 380 400 sulfid grams V I and inrsultidgra ns M ;V L W viscosity 154 viscosity 158 170 193 becomes so- A product obtained from o usion' with less sulfur gave the following results for 1000 grams of dyestuif calculated at a concentration'of 35% ot the dycstuil":

diam sulfi grams viscosity sullid grams viscosity 114 Example III. 3375 parts of a press-cake containing about 44 percent. of dry matter, as obtained by precipitating by means of air or acids the dycstuil solution made according to the process of German patent No. 127,835 andpressing the precipitate, required 400 art's ol' calcined sodium suliid containing about ofN:..,S, or 800 parts of crystallized sodium sulfid to produce 3775 )artsol' a concentrated dycstul'l' solution, winch foot. 1

117 122 177 18'5""2'31'" solid.

- about 180parts.

also already exhibits a satisfactory degree of liquidity (for example, a viscosity oi 162). The client of further proportions of sodium sullid for 100091, of concentrated dycstuil calculated at a concentration of the dyestull' solution of 39% inrespect o the dry dyostutl' used, was as follows: cryst. sodium 500- addit. o1'.crys't.sob! 120 l-tl) 300 430 splt| l ui'aiu.- d'uim sullldgrams in MM viscosity il'rJ viscosity 152 160 244 Example IV. 500 parts of a concentrated press-cake of about 557 )1} strength, obtained from a fusion of dinitro-oxy-diphenyla-min according to German patent No. 1()3,561, by precipitation with acids or even with air, required about 300 parts of crystallized sodium sultid to make it a thin liquid, which remains in that condition.

Example V. 500 parts of a press-cake of 36.5% strength, obtained by melting polysultid or boiling with an aqueous solution of polysullid the indophcnol O =C,,H ,=N(",,H (Nll htfl (1) are mixed with a gradually increasing quantity, amounting to 100, 200

and finally 360 parts, of fused crystallized sodium sulfid, whereby the thick paste passes, at 300 parts, into complete solution; as this by long standing becomes a thick liquid, yet another 100 parts of sodium sullid are added, whereupon a thin liquid is obtained, wlnleby addition of furtherproportions of sodium sullid such as another 200- 300 parts, a mass is produced which becomes solid on standing.

Example \I. 000 parts 01 a press-calm .of thiogene brown S, obtained by dissolving commercial thiogene-brown S in water, precipitating with acid and pressing, are stirred wltll a gradually increasing proportion of fused sodium sulfid, amounting finally to The concentrated solution" is a thin fluid and remains so on standing.

Having thus described our invention, we claim as new and desire to secure by Letters- Patent:

Thcprocass herein described of making highly concentrated liquid sulfurlzed dyestufl's, which consists in addlng to'the undriod dycstutl', obtained directly in its manufacture, sodium suliid in such proportions that tho dycstulf is transformed into a complete solution which preserves its liquid condition on standing.

In testimony, that we claim the foregoing as our invention, we have signed our names in presence of'two subscribing witnesses.

ALBRECHT SCHMIDT.

OTTO SCHWAB. Witnesses:

Amman Buisnois, 

